30 



SCIENCE 



[N. S. Vol. XXXII. No. 809 



rays, and how easy to overlook the emaller 

 ones. Couple with this the uncertainties ex- 

 pressed by Agassiz himself, and the fact that 

 he had only one workable specimen, and I 

 thinls: we are fully justified in concluding that 

 the supposed differences do not exist. It 

 would be in a measure rather remarkable if 

 they did. 



An examination of all our Superior speci- 

 mens of Eucalia fails to disclose, as mentioned 

 before, anything whatsoever to distinguish 

 them, or any of them, from Eucalia incon- 

 stans. Until better evidence is produced of 

 its existence, therefore, we believe that Eucalia 

 inconstans pygmwa Agassiz should be dropped 

 from our list of North American fishes. 



George Wagner 

 Wisconsin Geological and 

 jSTatueal History Survey, 

 May 1, 1910 



THE GEOLOGICAL SOCIETY OF AMERICA 



ELEVENTH ANNUAL MEETING OF 



THE CORDILLERAN SECTION 



The Cordilleran section of the Geological Society 

 of America held its eleventh annual meeting at 

 South Hall, University of California, Berkeley, 

 March 25-26, 1910. As officers for the ensuing 

 year were elected A. C. Lawson, chairman ; G. D. 

 Louderback, secretary, and H. F. Bain, councilor. 



The following papers were presented and dis- 

 cussed : 



The Limestone Plains of the Interior of Bahia: 

 J. C. Branneb, Stanford University, Cal. 

 Limestones, probably of Jurassic age, cover 

 many thousands of square miles in the interior 

 of Brazil, especially in the states of Bahia and 

 Minas Geraes. In many parts of the same region 

 valley floors are covered by recent limestone de- 

 posits spread out in horizontal sheets. These 

 later limestones appear to be derived from the 

 older ones by processes now in operation in the 

 same region in modified form. 



Geologio Work of Ants in Tropical Countries: 

 J. C. Bbanner, Stanford University, Cal. 

 Work of considerable geologic importance is 

 done in most tropical countries by certain ants 

 and by what are popularly called white ants. The 

 white ants are not ants at all, but belong to the 

 Isoptera. The present paper gives the results of 

 observations upon the abundance and habits of 



these insects, and the amount of earth moved by 

 them in excavating their underground galleries. 



Tables for the Determination of Crystal Classes: 



W. S. Tangier Smith, Reno, Nev. 



This paper presents two difi'erent keys for the 

 determination of crystals belonging to the thirty- 

 two crystal classes, according to their morphology. 

 One of these tables makes use of a center of sym- 

 metry as the basis for its main divisions, while 

 in the other the center of symmetry is not con- 

 sidered. It is intended that in practical use one 

 table may serve as a check upon the other. In 

 the second table the classes are grouped in ac- 

 cordance with the classification recently proposed 

 by Schwartz, while the class names are given 

 according to both Krause and Dana. 



The Occurren-ce of the Halogen Salts of Silver at 

 Tonopah, Nev.: J. A. Burgess, Tonopah, Nev., 

 and A. S. Eakle, Berkeley, Gal. 

 The occurrenc-e was described of the chlorides, 

 iodides, bromides of silver at Tonopah, and de- 

 scriptions given of these minerals and associated 

 minerals. 



A New Development at the Mouth of the Missis- 

 sippi: E. W. HiLGAED, Berkeley, Cal. 

 This refers to the uprising of a serious obstacle 

 to navigation outside of the Eads Jetties in the 

 south pass, which has been made the mean outlet 

 of the Mississippi and of navigation, on account 

 of its being the only one of the Mississippi 

 mouths showing no mud-lump activity. Professor 

 Hilgard predicted, however, in 1869 that when the 

 main current of the river was directed into the 

 pass, such activity would begin within twenty to 

 thirty years, as has now happened. 

 Contribution to the Geology of Eastern Oregon: 

 E. L. IcKES, Berkeley, Cal. 



A statement of the general stratigraphy and 

 structural features of eastern Oregon with a more 

 detailed discussion of certain formations and 

 structures specially studied during a recent field 

 trip in the east central part of the state. 



California Earthquakes — A Synthetic Study of 

 the Recorded Shocks: H. 0. Wood, Berkeley, 

 Cal. 



A correlation of recorded shocks with the known 

 faults of the region and especially with those sus- 

 pected to show recent activity. 



Secondary Pseudost ratification in Santa Barbara 

 County, Cal. : George D. Loudeeback, Berkeley, 

 Cal. 

 There has developed in Tertiary friable massive 



